Hi Bruce, from your description I would think that Rhino would be your best bet, as far as I can tell it is the most widely used thing for that sort of stuff in architecture where you want more unconventional or free flowing type forms, but also tools and plug-ins for helping with the manufacturing side of things.

The Gehry software is another choice I think that targets the entire workflow of custom shaping + buildability, I don't doubt that it would work well but I believe that it is very expensive.

Rhino is very inexpensive in comparison which tends to make it a lot easier to adopt.

MoI is a lot less expensive even yet, I mean so much so that it basically borders on being free in comparison to any of the other tools that you would use. So that makes it a pretty darn easy thing to adopt as a helper tool no matter which way you go in the end. MoI can create the same kind of NURBS geometry as Rhino and even uses the same file format, so it is something that works very easily in combination with Rhino.

It will be difficult for you to do only MoI and nothing else, because MoI does not currently have an extended ecosystem around it with custom manufacturing/paneling plugins, unwrapping-developable surfaces stuff, things like that which Rhino does have.

Your local CNC guy that recommends SolidWorks is likely used to making mechanical parts, which SolidWorks is often a better choice for than Rhino. But that does not line up with what it sounds like you want to do.

So I'd say focus on Rhino, and if you like the feel of drawing in MoI, just throw that in alongside of it and use a Rhino + MoI combination, you can actually copy and paste back and forth between them.

- Michael